Semiconductor memory devices using nonvolatile memory such as NAND flash memory have become widespread as media for storing data such as music data and video data. For example, SD cards are commonly used as external storage for electronic devices such as digital cameras and cellular phones.
There is now a demand that, as the capacity of nonvolatile memory increases, semiconductor memory device interfaces be capable of higher transfer rates when a host device writes and reads data. Some SD cards can transfer data at up to 104 MB/s, and development of techniques for further acceleration is well advanced in next-generation interfaces.
For systems with such advanced interfaces, various studies have been conducted to increase speed. For example, burst transmission of data packets at short intervals has been proposed in order to improve transfer efficiency. Such data bursting involves processing associated with responding to the reception of data packets, which can constitute an overhead. Specifically, it takes time to switch the input and output buffers in responding, and data packets cannot be transmitted separately when a data error occurs.
To reduce the time for switching buffers, an increased number of data packets may be transmitted during a data burst transmission period. This, however, requires an increased buffer size to temporarily store packets and an increased volume of data to be retransmitted, which is undesirable.